| // Copyright 2015 The Cobalt Authors. All Rights Reserved. |
| // |
| // Licensed under the Apache License, Version 2.0 (the "License"); |
| // you may not use this file except in compliance with the License. |
| // You may obtain a copy of the License at |
| // |
| // http://www.apache.org/licenses/LICENSE-2.0 |
| // |
| // Unless required by applicable law or agreed to in writing, software |
| // distributed under the License is distributed on an "AS IS" BASIS, |
| // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| // See the License for the specific language governing permissions and |
| // limitations under the License. |
| |
| #ifndef COBALT_LAYOUT_LETTERBOXED_IMAGE_H_ |
| #define COBALT_LAYOUT_LETTERBOXED_IMAGE_H_ |
| |
| #include <vector> |
| |
| #include "base/optional.h" |
| #include "cobalt/math/rect_f.h" |
| #include "cobalt/math/size_f.h" |
| |
| namespace cobalt { |
| namespace layout { |
| |
| struct LetterboxDimensions { |
| // The destination dimensions of the image such that its aspect ratio is |
| // maintained. |
| base::Optional<math::RectF> image_rect; |
| |
| // A set of filling rectangles that pad the image. |
| std::vector<math::RectF> fill_rects; |
| }; |
| |
| // This helper function will compute the dimensions of an image and filling |
| // rectangles such that the image appears at the correct aspect ratio within |
| // a letterboxed destination rectangle. This function will return the |
| // dimensions to use for an image and all filling rectangles (which will |
| // presumably be filled as solid black) in order to create the letterbox effect. |
| // It does the above by the following steps: |
| // 2. If the area of the Image is 0, this function will return a single filling |
| // rectangle covering the entire |destination_size|. |
| // 3. If the aspect ratio of the image is the same as |destination_size|, the |
| // image will be stretched to fill the whole destination. |
| // 4. If the image is wider than the destination, it will be stretched to ensure |
| // that its width is the same as the width of the destination. The image |
| // will be centered vertically and two filling rectangles placed on the top |
| // and bottom to fill the blank. |
| // 5. Otherwise, the image is higher than the destination. it will be stretched |
| // to ensure that its height is the same as the height of the destination. |
| // The image will be centered horizontally and two filling rectangles placed |
| // on the left and right to fill the blank. |
| LetterboxDimensions GetLetterboxDimensions(const math::SizeF& image_size, |
| const math::SizeF& destination_size); |
| |
| } // namespace layout |
| } // namespace cobalt |
| |
| #endif // COBALT_LAYOUT_LETTERBOXED_IMAGE_H_ |